Walking and running can be defined as methods of locomotion involving the use of the two legs, alternatively, to provide both support and propulsion, with at least one foot being in contact with the ground at all times. While the terms gait and walking are often used interchangeably, the word gait refers to the manner or style of walking, rather than the actual walking process. The gait cycle is the time interval between the exact same repetitive events of walking.
The defined cycle can start at any moment, but it typically begins when one foot contacts the ground and ends when that foot contacts the ground again. If it starts with the right foot contacting the ground, then the cycle ends when the right foot makes contact again. Thus, each cycle begins at initial contact with a stance phase and proceeds through a swing phase until the cycle ends with the limb's next initial contact. Stance phase accounts for approximately 60 percent, and swing phase for approximately 40 percent, of a single gait cycle.
However following injury or surgery to the foot, a patient may be fitted with a walker to assist in locomotion. Various devices that allow a patient to continue the normal gait cycle are known, for example casts, braces, cuffs, splints, soft boots, hard boots and the like, which are designed to protect and stabilize the foot following injury or surgery. However, most of these devices are constructed such that the patient's foot is still subjected to all the impact force when it hits the ground. Hard surfaces in modern human environments have changed the forces encountered by the human musculoskeletal system during the gait cycle as compared to the forces which it evolved to sustain. Impact energies from such surfaces enter the body through boney and dense tissues and through soft and fatty tissues. When a patient is trying to recover from injury or surgery, such impact energy frequently exacerbates the injury.
Other causes of injury to the foot relate to underlying pathological disease states, such as by way of example, diabetes. Diabetes is a chronic disease that affects up to six percent of the population in the U.S. and is associated with progressive disease of the microvasculature. Complications from diabetes include not only heart disease, stroke, high blood pressure, diabetic retinopathy but also in particular diabetic neuropathic foot disease.
Diabetic neuropathic foot disease typically results in the formation of ulcers which commonly result from a break in the barrier between the dermis of the skin and the subcutaneous fat that cushions the foot during ambulation. This rupture may lead to increase pressure on the dermis. In order for the ulcer to heal, the patient must either stay off their feet altogether or use a pressure relieving orthotic or brace.
While there are devices and methods that purport to prevent planar ulcer formation in a diabetic patient there are no devices on the market that treat the ulcer with dynamic offloading of the weight bearing limb.
Therefore, what is needed is a system and method that can be used to mitigate excessive impact forces on an injured foot during locomotion or off-load an injured, weight bearing limb during locomotion while allowing a patient to maintain normal gait function.